The better question to ask yourself is how stiff the competition is among the top 10 or 20 sites.

After all, obtaining a ranking at position 81 is going to get you just about as much traffic as being ranked at position 31,551.

Look more closely at the Top 10 sites, maybe Top 20 in more competitive fields, and figure out how well they are optimized. That'll tell you a lot more about how much work it's going to take to get your site up with the big boys.